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Message-Id: <20231002-ccf-set-multiple-v1-1-2df5e9eb3738@skidata.com>
Date: Mon, 02 Oct 2023 11:23:32 +0200
From: Benjamin Bara <bbara93@...il.com>
To: Maxime Ripard <mripard@...nel.org>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>
Cc: Frank Oltmanns <frank@...manns.dev>,
Adam Ford <aford173@...il.com>, linux-clk@...r.kernel.org,
linux-kernel@...r.kernel.org,
Benjamin Bara <benjamin.bara@...data.com>
Subject: [PATCH RFC 1/4] clk: only set req_rate if it is set by consumer
From: Benjamin Bara <benjamin.bara@...data.com>
Currently, the req_rate is set during initialization and during
re-parenting. Therefore, it is not clear whether the req_rate is really
required by a consumer or just set by accident. Fix this by only setting
the req_rate when it is really required (clk_set_rate() is called by
consumer).
Signed-off-by: Benjamin Bara <benjamin.bara@...data.com>
---
drivers/clk/clk.c | 37 ++++++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 13 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index c249f9791ae8..82f954121e4d 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -24,6 +24,8 @@
#include "clk.h"
+#define CLK_RATE_UNSET -1UL
+
static DEFINE_SPINLOCK(enable_lock);
static DEFINE_MUTEX(prepare_lock);
@@ -1832,7 +1834,6 @@ static unsigned long clk_recalc(struct clk_core *core,
/**
* __clk_recalc_rates
* @core: first clk in the subtree
- * @update_req: Whether req_rate should be updated with the new rate
* @msg: notification type (see include/linux/clk.h)
*
* Walks the subtree of clks starting with clk and recalculates rates as it
@@ -1842,8 +1843,7 @@ static unsigned long clk_recalc(struct clk_core *core,
* clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
* if necessary.
*/
-static void __clk_recalc_rates(struct clk_core *core, bool update_req,
- unsigned long msg)
+static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
{
unsigned long old_rate;
unsigned long parent_rate = 0;
@@ -1857,8 +1857,6 @@ static void __clk_recalc_rates(struct clk_core *core, bool update_req,
parent_rate = core->parent->rate;
core->rate = clk_recalc(core, parent_rate);
- if (update_req)
- core->req_rate = core->rate;
/*
* ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
@@ -1868,13 +1866,13 @@ static void __clk_recalc_rates(struct clk_core *core, bool update_req,
__clk_notify(core, msg, old_rate, core->rate);
hlist_for_each_entry(child, &core->children, child_node)
- __clk_recalc_rates(child, update_req, msg);
+ __clk_recalc_rates(child, msg);
}
static unsigned long clk_core_get_rate_recalc(struct clk_core *core)
{
if (core && (core->flags & CLK_GET_RATE_NOCACHE))
- __clk_recalc_rates(core, false, 0);
+ __clk_recalc_rates(core, 0);
return clk_core_get_rate_nolock(core);
}
@@ -2455,7 +2453,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
/* change the rates */
clk_change_rate(top);
- core->req_rate = req_rate;
err:
clk_pm_runtime_put(core);
@@ -2485,6 +2482,7 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
*/
int clk_set_rate(struct clk *clk, unsigned long rate)
{
+ unsigned long old_req_rate;
int ret;
if (!clk)
@@ -2493,6 +2491,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
+ old_req_rate = clk->core->req_rate;
+ clk->core->req_rate = rate;
+
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
@@ -2501,6 +2502,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
if (clk->exclusive_count)
clk_core_rate_protect(clk->core);
+ if (ret)
+ clk->core->req_rate = old_req_rate;
+
clk_prepare_unlock();
return ret;
@@ -2528,6 +2532,7 @@ EXPORT_SYMBOL_GPL(clk_set_rate);
*/
int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
{
+ unsigned long old_req_rate;
int ret;
if (!clk)
@@ -2536,6 +2541,9 @@ int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
+ old_req_rate = clk->core->req_rate;
+ clk->core->req_rate = rate;
+
/*
* The temporary protection removal is not here, on purpose
* This function is meant to be used instead of clk_rate_protect,
@@ -2546,6 +2554,8 @@ int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
if (!ret) {
clk_core_rate_protect(clk->core);
clk->exclusive_count++;
+ } else {
+ clk->core->req_rate = old_req_rate;
}
clk_prepare_unlock();
@@ -2723,7 +2733,7 @@ static void clk_core_reparent(struct clk_core *core,
{
clk_reparent(core, new_parent);
__clk_recalc_accuracies(core);
- __clk_recalc_rates(core, true, POST_RATE_CHANGE);
+ __clk_recalc_rates(core, POST_RATE_CHANGE);
}
void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
@@ -2807,9 +2817,9 @@ static int clk_core_set_parent_nolock(struct clk_core *core,
/* propagate rate an accuracy recalculation accordingly */
if (ret) {
- __clk_recalc_rates(core, true, ABORT_RATE_CHANGE);
+ __clk_recalc_rates(core, ABORT_RATE_CHANGE);
} else {
- __clk_recalc_rates(core, true, POST_RATE_CHANGE);
+ __clk_recalc_rates(core, POST_RATE_CHANGE);
__clk_recalc_accuracies(core);
}
@@ -3706,7 +3716,7 @@ static void clk_core_reparent_orphans_nolock(void)
__clk_set_parent_before(orphan, parent);
__clk_set_parent_after(orphan, parent, NULL);
__clk_recalc_accuracies(orphan);
- __clk_recalc_rates(orphan, true, 0);
+ __clk_recalc_rates(orphan, 0);
/*
* __clk_init_parent() will set the initial req_rate to
@@ -3888,7 +3898,8 @@ static int __clk_core_init(struct clk_core *core)
rate = parent->rate;
else
rate = 0;
- core->rate = core->req_rate = rate;
+ core->rate = rate;
+ core->req_rate = CLK_RATE_UNSET;
/*
* Enable CLK_IS_CRITICAL clocks so newly added critical clocks
--
2.34.1
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